Liberty has been rare in human history. In this sweeping account of the rise of the modern world, Acemoglu and Robinson argue that only in rare circumstances have states managed to produce free societies. States have to walk a thin line to achieve liberty, passing through what the authors describe as a “narrow corridor.” To encourage freedom, states must be strong enough to enforce laws and provide public services but also restrained in their actions and checked by a well-organized civil society. The authors call those states that tread this path “Shackled Leviathans,” governments dedicated to upholding the rule of law, protecting the weak against the strong, and creating the conditions for broad-based economic opportunity. Acemoglu and Robinson argue that it was in medieval Europe that states began to find the balance that created the conditions for liberty and economic advancement. They had inherited top-down centralizing institutions from the Roman Empire and bottom-up participatory dynamics from the Germanic tribes that had invaded Rome. Chapters on China, India, the United States, and the Middle East; on the crises of liberal democracy in places such as Weimar Germany; and on modern-day populist movements reinforce the notion that liberty is deeply contingent and often ephemeral.